Plow with symmetrical bodies having concave vertical and horizontal cross-sections

ABSTRACT

A plow having symmetrical mold-boards and bodies, the plow comprising a hitch 1 connected in particular by means of a pivot 3 and to a main frame 4 which is provided with a pivot 18 receiving a hydraulic actuator 17 whose action causes a beam 8 to pivot about its axis 7 together with body carrier elements 10 provided with mold-boards 11, characterized by a symmetrical moldboard 11 having a concave working surface which is horizontally hollow 46 and vertically hollow 47, with each of its side ends taken in a front position tapering upwardly rearwardly, by a single deflector 45 for both working directions in the form of a sector of a melon, by a strut 10 comprising a safety system including two elements 36 and 78 capable of moving longitudinally relative to each other, and by a pivoting rear rudder blade.

The present invention relates to a plow with one or more bodies eachhaving a share and a mold-board of a special symmetrical shape, withvariable working width and angle and intended to be connected to atractor provided with a hitch for a trailed tool or with a two or threepoint linkage for a mounted or a semi-mounted tool.

In the past, changing the working direction as required by so-called"flat" plowing has been done by rotating the body-carrying frame whichis fitted with "righthand" bodies and with "lefthand" bodies, therebyincreasing the number of parts, and increasing the weight of the plow tothe detriment of plow price and tractor performance. Each body isprovided with a side piece called a "landside" bearing against the wallof the furrow and intended to prevent the plow from skidding sideways byvirtue of the force exerted on the mold-board by the earth, with themold-board being at an angle of attack α to the line of advance. Thepresence of the landsides further increases length, since the strip ofearth to be turned over can do so freely only after each landside fixedon the preceding body has gone past.

The principle of symmetrical bodies is known, but their mold-boardsconstituted by elements which are cylindrical or semi-helical in shapeand of excess length at the top both behind and in front, suffer from alack of vertical trailing angle going backwards and downwards, therebygiving rise to front end clogging leading to insufficient penetrationand to irregular burying of organic matter. Further, the junctionbetween the outside side face of the plow share and the front,spur-shaped base of the mold-board constitutes an angle in whose hollowground roots are retained, causing clogging to take place more quicklyon entry into the ground when the same side face of the mold-board isused the next time.

Finally, plow body safety systems are known enabling the edge of theplow share to rise in a vertical plane which moves horizontally more orless parallel to the ground, with it being possible to retract the sharewhose tip pivots about an axis, however these two operations do not takeplace simultaneously and each of them presents its own drawback, withthe first drawback being that the body takes up the selected depth overtoo long a distance, and the second being a mold-board which isvertically directed and which does not turn over the earth, with thissecond drawback occurring on all other systems having a share whichpivots about a single direction about a pivot or an infinity ofdirections about a point.

The present invention seeks to provide possible ways of satisfying theabove-mentioned drawbacks and insufficiencies and to provide solutionswhich are more effective and/or less expensive by proposing:

1. A special shape of symmetrical mold-board and share that plowproperly in both working directions.

2. A rudder principle guiding the plow and replacing all of thelandsides.

3. A single safety system for both working directions.

The various portions of the invention will be better understood fromreading the following description and from examining the accompanyingdrawings which show several embodiments of the various elements used inthe invention by way of non-limiting example.

In the drawings:

FIG. 1 is a plan view of a plow in accordance with the invention at workturning earth over to the right.

FIG. 2 shows the same assembly in longitudinal section with thebody-carrying beam in its middle position.

FIG. 3 shows the shape of a conventional body.

FIG. 4 shows the shape of a body, mold-boards, and share in accordancewith the invention.

FIG. 5 and 5a show a rear rudder positioned on the rear body orcontrolled by the system for pivoting the bodies on the beam.

FIG. 6 is a profile view of a multi-direction safety system.

FIG. 7 is a rear half view of the same assembly.

FIG. 8 is a detailed perspective view of the running path of the safetysystem.

The assembly constituted by FIGS. 1, 2, and 5 bis comprises a hitchframe 1 having pins 2 which are hitched to the draw bars of the tractor,and a pivot shaft 3 which connects it to the main frame 4 which pivotsthereon. The horizontal rear portion of the main frame 4 is providedwith a vertical pivot 7 about which the beam 8 swivels from right toleft and vice versa, said beam 8 being fitted with a plurality of pivots9 to which the elements for working the ground, i.e. the mold-boards 11and the shares 12 are fixed via soles 36 and supports 10. Instead of arigid strut 10, each pivot 9 may receive an optional safety system asdescribed below between itself and its sole 36. Each pivot 9 has a crank13 fixed thereon, with the cranks all being coupled to a link 14. One ofthe pivots 9 has an additional crank 15 provided with a terminal pin 16which receives the piston rod of a hydraulic actuator 17 whose other endswivels about an axis 18 which is fixed to the main frame 4. Two sets ofadjustable abutments 19 and 20 are fixed respectively on the beam 8 andon the frame 4 and serve respectively to limit the amplitude of thebodies relative to the beam delimiting the body attack angle, and thestroke of the beam delimiting the total working width of the bodies. Arudder 21 situated behind the last share is fixed to the bottom portionof a post 22 which pivots relative to the beam 8 and which is rigidlyconnected to a gear wheel 23 meshing with another gear wheel 24 fixed tothe last pivot 9 or to any other link means between the post 22 and thepivot 9.

The assembly shown in FIG. 3 comprises a conventional plow body having amold-board 41 with all of its horizontal generator lines being straightor convex going rearwards, thereby requiring a long mold-board in orderto turn over the strip of earth properly since otherwise the earth fallsdown behind it without being turned over sufficiently. The leadingattack angle α formed by a horizontal generator line and a line ofadvance parallel to the landside 42 is large enough to mean that thepressure on the mold-board requires a landside to extend over the entirelength of the body in order to prevent the plow from skidding sideways.For a given angle α, the longer the mold-board, the greater adherence ofthe earth requires additional traction power over and above thatrequired by the lateral pressure of the landside 42 against the wall ofthe furrow against which it is pressed.

FIG. 4 shows an assembly constituting a body in accordance with theinvention. In accordance with the invention, the working face of themold-board 11 has a concave surface horizontally and vertically, theconcavity extending over all or a portion of the surface of themold-board, 11. The mold board 11 has a horizontal section 46, which isseen superimposed on FIG. 5, the section being concave to the degree asseen at the upper line of horizontal section 46 seen in FIG. 4. Thevertical section 47 of the mold board is also superimposed on FIG. 4 andis also concave, with the degree of concavity seen at the righthand lineof superimposed vertical section 47. The horizontal concavity seen at 46is concave to an extent which can correspond to a given type of earth tobe plowed, and with the degree of concavity varying from bottom to top.The concavity is generally more marked at the top in order to accentuateturning over, thereby reducing the effective working length of themold-board over which earth passes. The mold-board angle of attack α issmaller, thereby avoiding the use of a landside on the body. Such a bodywhich is concave in two directions, i.e. horizontally 46 and vertically47, gives rise to a mold-board which is shorter at the top and givesrise to reduced lateral force, thereby requiring less tractive power.

In addition, in order to avoid a sharp angle that would slow down theflow over the share/mold-board junction of debris such as roots orplants, said junction has a curved portion 48 in accordance with theinvention.

The assembly shown in FIG. 5 comprises a vertically directed shaft 51having a guide plate 21 at its bottom end with the bottom edge of theguide plate being situated substantially at the same level as the bottomof the share 12, said shaft pivoting in a sleeve 52 which is fixed tothe strut 10 with the top end of the shaft being fitted with a stay 53which comes into contact with one or other of two abutments 54,depending on the working direction, said abutments being adjustabledepending on the angle of attack adopted for the body. Instead of beingfixed to the strut 10, the sleeve 52 could be received in the beam 8, inwhich case the shaft 22 (see FIG. 5a) would be connected to the control14 for pivoting the bodies via a connection 55 for pivoting the ruddersat the same time as the bodies are pivoted.

The assembly constituted by FIGS. 6, 7, and 8 comprises: the top portion74 of the strut connected to the pivot 9 by a plate 75 and a hinge 76whose oscillation is limited by a flexible abutment 77; and a rigid railportion 78 on the top portion 74 in which at least one wheel 79 runs,said wheel being supported by a shaft fixed on the sole 36 whichreceives the mold-board 11 and the share 12 and also the ends 80 of apair of flexible links 81, each of whose top ends oscillate about arespective pin 82 fixed to the plate 75.

Operation is as follows:

When the tractor arrives at the end of the field in order to returnalong the line left by the last body, e.g. by righthand plowing, theplow is lifted off the ground, the hydraulic actuator 18 is actuated,the beam 8 leaves its right abutment 20, and continues its stroke untilits encounters the left abutment 20. If the crank 15 pulled by thehydraulic actuator rod does not move during pivoting, then after thebeam 18 makes contact with the abutment 20, the actuator thrusts thecrank 15 until contact is made with the left abutment 19 at the leadingangle of attack selected for the bodies.

In its displacement, the control 14 linking the cranks 13 and the pivots9 also causes the rear rudder 21 to pivot from right to left.

When the bodies are protected by a safety system, with the skimmersbeing controlled hydraulically and independently for each body in orderto avoid untimely displacements thereof during movements of the safetysystem, and when the portion in the ground (the share or the mold-board)encounters an obstacle, then various different movements are possible:if the obstacle, e.g. a stone, is situated at the front, the body tiltsabout the wheel support axis 79 while the wheel runs along the rail 78,thereby compressing resilient systems which reposition the body afterthe obstacle has been passed; if the obstacle is situated towards theback or in the middle, the body rises as guided by the wheel in the rail78 and may also cause the top portion 74 and the rail to pivot about thetop axis 76. Finally, the three motions: tilting, running of the wheel,and pivoting about the top axis, may be provoked simultaneously underpressure from the resilient systems 81. In most cases, the body movesclose to and parallel with the ground, thereby ensuring betterprotection of the plow overall from the point of view of mechanicalstrength and also providing greater continuity in the turning over ofthe earth.

I claim:
 1. A plow system adapted to be pulled by a pulling means andfurther adapted for two-way plowing whereby the plow will throw plowedearth in a first geographic direction to a first side of the pullingmeans when the pulling means advances in a first geographic sense, and,when the pulling means returns in a second geographic sense, 180° fromthe said first geographic sense, will throw plowed earth in the samesaid first geographic direction but to the opposite side of thereturning pulling means, the plow system including:at least onemoldboard (11); a first support means (10) for supporting said moldboard(11), said first support means (10) being operatively connected to saidmoldboard (11); a second support means for supporting said first supportmeans, said second support means including a main beam (8), the firstsupport means being pivotably connected to the second support means;means for connecting (1, 4) said second support means to the saidpulling means so that the second support means is positioned at an acuteangle to the direction of travel of said pulling means with the forwardportion of the second support means directed to one side of the pullingmeans when the pulling means advances in a first geographical sense soas to throw plowed earth in said first geographical direction; means foraltering (17, 18) the relation of the second support means to thepulling means so that the forward portion of the second support means isdirected to the opposite side of the pulling means when the pullingmeans returns in a second geographical sense, 180° from the said firstgeographical sense so as to throw plowed earth in the same said firstgeographical direction; said moldboard (11) having a surface whichcontacts and throws the earth being plowed which is at least partiallyconcave, this concave surface being concave in its horizontal section(46) as well as being concave in its vertical section (47), wherein thesaid surface of the moldboard has a concavity in its horizontal sectionwhich has a substantially shorter radius of curvature at the upperportion of the moldboard than at the lower portion of the moldboard. 2.A plowing system according to claim 1 including a share, the share beingconnected to the moldboard (48), and wherein the leading edge of theshare-moldboard, when the share-moldboard is viewed from the side, isconcave.